A power source apparatus for an electric automobile is provided with a battery system, having a driving battery to power an automobile driving motor and a battery control circuit to control driving battery charging and discharging as well as to compute driving battery remaining capacity, and an accessory battery to power automobile electrical accessories. When the automobile is in the stationary state a, charging circuit, which controls charging between the driving battery and accessory battery, charges the driving battery to a specified state with accessory battery power. The battery control circuit corrects the value of driving battery remaining capacity to a specified battery capacity, and subsequently charges the accessory battery with the driving battery to bring driving battery remaining capacity to a specified level.